1. Field of the Invention
The present invention relates to liquid pump dispensers and more particularly to such pump dispensers where dosage dispensing is important and prevention of overdosing or underdosing is also important. Thus, the present invention involves such dispensers that require complex movements for each dosage dispensation to avoid an accidental second pumping or an accidental underpumping.
2. Information Disclosure Statement
The following patents are examples of the prior art relating to dispensing mechanisms including metered dispensers:
U.S. Pat. No. 5,615,806 to Grothoff describes a pump dispenser which has a plunger lock-up feature in which the plunger is positively retained against dislodgement by cradling projections on the piston stem against abutment shoulders of a locking sleeve which is fixed within the pump body of the dispenser. The pump body may be of an integral one-piece construction with the container closure, and the container vent opening is controlled by an upstanding sleeve on the piston cup for preserving the integrity of the piston seals.
U.S. Pat. No. 5,277,334 to Malinconico describes an acquisition device of a discharge apparatus which is operated by a servodrive, which has at least one control cam constantly engaging in cam path. The control cam is directly provided on the actuating cap for the discharge actuator, while the cam path is located on the circumference of a fastening cap for the discharge feeder, so that no additional component is required for forming the acquisition device.
U.S. Pat. No. 4,915,601 to Schuckmann describes a dosaging pump which can be placed, in particular, on bottles or the like, having a pump bellows and two valves, one of which is associated with the inlet side and the other with a nozzle. The nozzle-side vale-closure member is seated in the cover of a cap which grips over the pump bellows. A cup surrounds the pump bellows, the inlet-side valve-closure member being seated in the bottom of the cup. End portions of the pump bellows are seated on separate collars of the cup and the cap, the cap and cup being moveable relative to each other during pumping, and the valve-closure members communicate with the interior of the bellows.
U.S. Pat. No. 4,589,574 to Foster shows serrations on the upper end of the pump body which are disposed for interlocking engagement with depending portions of the pump collar so that when the plunger is rotated in a counterclockwise direction to unlock the same from the collar in preparation for reciprocal operation, the collar is held securely by the body against rotation to assure unlocking. The serrations take the form of plurality of equally circumferentially spaced ramps which are inclined in the direction of locking rotation of the plunger to thereby permit the collar to yieldably override the serrations when the locked plunger and collar are rotated as a unit in the locking direction relative to the body to orient a spout of the plunger in a desired location for factory packaging efficiency.
U.S. Pat. No. 4,589,573 to Tada describes a head depression type dispenser which comprises a cylinder formed of an elastic material such as rubber. The cylinder is arranged between a head and a cap, and is constructed to operate as a piston for sucking and pressurizing liquid by axial deformation of the cylinder upon movement of the head. When the depressing force applied to its head is removed after the cylinder is deformed, the cylinder will return to the original shape by its own elasticity. In addition, a sealing piece extends from the cylinder into the passage of the head, thereby closely contacting the inner wall of the passage to form a secondary valve. The sealing piece becomes isolated from the inner wall of the passage when the hydraulic pressure in the cylinder exceeds the elasticity of the sealing piece, allowing the flow of the compressed liquid through the passage, and closely contacts the inner wall of the passage by the elasticity of the sealing piece when the hydraulic pressure is becomes lower than the elasticity of the sealing piece. Since the cylinder can deform in its axial direction, it can be sufficiently deformed, thereby sufficiently pressurizing the liquid to a high pressure.
U.S. Pat. No. 3,422,996 to Lipman describes an actuator cap which is intended for use on hand-held dispensers such as pump-type or pressurized aerosol cans, and comprises a depress button which is vertically movable in a stationary cap attachable to the container of the dispenser. The button is also turnable between limits, and is blocked against downward movement for all of its rotative positions except the position defined by one of said limits.
Notwithstanding the prior art, the present invention is neither taught nor rendered obvious thereby.